apr-dev mailing list archives

Hi everyone,
In the discussion around the error reporting of dlopen() errors when
loading APR database drivers, I have understood that
* currently, only the fact that a driver failed to load can be
reported back to the caller
* the caller gets APR_EDSOOPEN when dynamic loading failed, but no clue
about the name of the file which caused the error.
At the moment, APU_DBD_DRIVER_FMT describes the format that is used
internally in apr_dbd.c to build the name of the shared object, from
the value of the APU_DSO_LIBDIR macro (which is apu-private from
apr-util/include/private/apu_config.h) and the name of the driver,
by using:
#define APU_DBD_DRIVER_FMT APU_DSO_LIBDIR "/apr_dbd_%s.so"
...
apr_snprintf(path, sizeof path, APU_DBD_DRIVER_FMT, name);
1)
This is going to break badly if APR is installed into a directory
that is called, say,
/my/na%sty/apr-lib/
because then the two %s are both interpreted as string expansion
format chars, and apr will probably dump core.
Suggestion:
use
#define APU_DBD_DRIVER_FMT "%s/apr_dbd_%s.so"
and
apr_snprintf(path, sizeof path, APU_DBD_DRIVER_FMT, APU_DSO_LIBDIR, name);
this should protect against directories with '%' characters.
2) the APU_DBD_DRIVER_FMT should IMO not be public at all, but
should be even more local (local to apr_dbd.c) -- its usage semantics
are highly specific to apr_dbd.c
3) For finding out the name that caused dynamic loading to fail, the
interface of the function doing the loading --apr_dbd_get_driver()--
should either be extended to allow for returning the absolute path
of the failing shared lib,
or a new function should be added that returns the name of the
shared object in question, when given the same driver name as
apr_dbd_get_driver(), something like
/* Get the absolute path of the driver's shared object */
apr_status_t apr_dbd_get_driver_dso_path(apr_pool_t *pool,
const char *name,
char **returned_name);
that fails with APR_ENOTIMPL if !defined(APU_DSO_BUILD)
What do you think?
Martin
--
<Martin.Kraemer@Fujitsu-Siemens.com> | Fujitsu Siemens
http://www.fujitsu-siemens.com/imprint.html | 81730 Munich, Germany